Epigenetic tuning of PD-1 expression improves exhausted T cell function and viral control

Nat Immunol. 2024 Oct;25(10):1871-1883. doi: 10.1038/s41590-024-01961-3. Epub 2024 Sep 17.

Abstract

PD-1 is a key negative regulator of CD8+ T cell activation and is highly expressed by exhausted T cells in cancer and chronic viral infection. Although PD-1 blockade can improve viral and tumor control, physiological PD-1 expression prevents immunopathology and improves memory formation. The mechanisms driving high PD-1 expression in exhaustion are not well understood and could be critical to disentangling its beneficial and detrimental effects. Here, we functionally interrogated the epigenetic regulation of PD-1 using a mouse model with deletion of an exhaustion-specific PD-1 enhancer. Enhancer deletion exclusively alters PD-1 expression in CD8+ T cells in chronic infection, creating a 'sweet spot' of intermediate expression where T cell function is optimized compared to wild-type and Pdcd1-knockout cells. This permits improved control of chronic infection without additional immunopathology. Together, these results demonstrate that tuning PD-1 via epigenetic editing can reduce CD8+ T cell dysfunction while avoiding excess immunopathology.

MeSH terms

  • Animals
  • CD8-Positive T-Lymphocytes* / immunology
  • Enhancer Elements, Genetic / genetics
  • Epigenesis, Genetic*
  • Lymphocyte Activation / immunology
  • Lymphocytic Choriomeningitis / immunology
  • Lymphocytic Choriomeningitis / virology
  • Mice
  • Mice, Inbred C57BL*
  • Mice, Knockout*
  • Programmed Cell Death 1 Receptor* / genetics
  • Programmed Cell Death 1 Receptor* / metabolism

Substances

  • Programmed Cell Death 1 Receptor
  • Pdcd1 protein, mouse